/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.runtime.core.util.counters;

import org.mule.runtime.api.meta.NamedObject;

/**
 * This interface is the interface implemented for all counter types. A Counter can represent a real counter or a virtual counter
 * that will be computed using one or more other counters.<br/>
 * <h3>Real counters</h3> are counters which represent real values. The user will call methods of such counters to modify the
 * associated value of the counter.
 * <h3>Computed counters</h3> are computed using one or more associated counters. Such counters represent operations computed on
 * associated counters. Usually, these counters will never be used directly, but will only used to retrieve the computed values.
 */
public interface Counter extends NamedObject {

  /**
   * Accessor for the counter type.
   * 
   * @return the type of the counter
   */
  CounterFactory.Type getType();

  /**
   * Increment the counter's value by 1.0.
   * 
   * @return the new value of the counter
   */
  double increment();

  /**
   * Increment the counter's value by the specified amount.
   * 
   * @param value the amount to increment the counter by
   * @return the new value of the counter
   */
  double incrementBy(double value);

  /**
   * Decrement the counter's value by 1.0.
   * 
   * @return the new value of the counter
   */
  double decrement();

  /**
   * Set the counter's value to a new value.
   * 
   * @param value the new value of the counter
   */
  void setRawValue(double value);

  /**
   * Compute and return the value of the counter.
   * 
   * @return the value of the counter
   */
  double nextValue();

}
